Koch Institute investigators have been pioneers in the use of animal models to study the molecular basis underlying the genesis and progression of cancer and are at the forefront of using animal modeling to address cancer detection and treatment. The Histology Core Facility has an outstanding histotechnology staff that provides cutting-edge histological expertise to all cancer researchers utilizing in vivo models. This expertise includes all aspects of histological analysis, from processing and secfioning to specialized staining and pathologic examination of fissue samples. Investigator training, from slide preparation to analysis, is another core component of this Core's mission. In addition, the Center continues to benefit from intellectual insight provided by veterinary pathologist, Dr. Roderick Bronson, an internationally recognized expert in mouse pathology. Dr. Bronson has made invaluable contribufions to the characterizafion of developmental and tumor phenotypes, and has trained numerous Kl students, fellows and staff in histopathology. This has fostered exchange of intellectual expertise between Core staff and Center member laboratories and has played a significant role in strengthening the integrafive nature of the Kl research program. Centralizing histological analyses under the auspices of the shared Histology Core allows us to capitalize on economies of scale and thereby provide cancer researchers a comprehensive and robust range of services. Over the current funding period, there has been a significant increase in the demand for these services, reflecting the broadening use of animal models by Center members. The Histology Core has responded to this need by increasing staff size and acquiring new instrumentation, which have enabled significanfiy greater and more efficient sample throughput. Accordingly, Core output in the immediate past funding year was substanfially increased in all service categories in comparison to the last competing renewal. Based on continually increasing demand, addifional service enhancements are planned for the requested funding period, which will allow us to expand both the usage and the Core Facility offerings without affecting the turnaround time for services.